The present invention provides an improved form of the compound 3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-beta-phenethylamin e, which is an intravenously administered agent for increasing cardiac contractility. It is not marketed orally in view of impractically large dosage that would be needed for 3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-beta-phenethylamin e for oral administration. 3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-beta-phenethylamin e is disclosed in Tuttle et al., U.S. Pat. No. 3,987,200, granted Oct. 19, 1976, and entitled Method for Increasing Cardiac Contractility. The present invention provides a complex of 3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-beta-phenethylamin e with cyclodextrin. Cyclodextrins have been known in the art for many years prior to the invention described in the Tuttle et al. patent, for example, Cohen et al., "Interaction of Pharmaceuticals with Schardinger Dextrins I", Journal of Pharmaceutical Sciences, Vol. 52, pp. 132-136 (1963).